Here is the scenario:

For me, personally, it depends on the person.

I have clients I love too - in my own fashion.

I have a hard rule of not mixing business and personal(learned that lesson the hard way).  As long as he doesn't start crossing boundaries everything is fine, but truthfully it does usually signal the end of relationship is coming soon. Which is a downer sometimes. its part of the deal, the human condition and all.

If she's never given you anything beyond the alotted appointment time, then she's definitely not interested in anything more than your current professional relationship. Saying "I love you" is the quickest way to get dropped as a client.  

As long as he doesn't expect me to tell him I love him too at that very moment.  So I may just say thanks, or you too.  

Freaking ways is this question going to be asked.  Hookers don't want boyfriend-girlfriend relationships with their clients.  Enough said.

"some" hookers are more than open to be in a BF-GF relationship with a former client. I am living proof of that.  

me thinks you have fallen for a gal, and want to see if and how you should proceed.

Do you have a name for Opey's syndrome? Perhaps IFAICGU ? Has anyone written a White Paper on this that we each can turn to in times of need?

I LOVE your line about kicking a kitten. truer words have never been spoken.

EVER say this to  client?

Not my issue and I am in this for the money. He is a regular and that means regular income. I am not about to mess with that. I have a couple of guys who have told me they love me.  I do not want a boyfriend or a husband. I want clean reliable clients and I do what it takes to keep them. The guys I see are "just clients".

become more of friends than business.  You know how things can evolve after a while.  I am able to seperate friendship love from romantic love, and can love a 'client' yet not want to date him or ask him to leave his wife.  By the way, this is not some guy I've seen 3, 5, or even 10 times.  This is a feeling that develops over years and various life situations with him.  We (clients and I who mutually love eachother) are both experienced enough in the hobby to "get it" and not impose our feelings in a way that cause eo problems.

if you're worried about it, bring it up with her and talk things out. I think for your peace of mind you need to know where you stand with her. It can help clear the air. Trust me, when you feel that way about a lady, it's better to know.  Of course, before you do, you need to think about how you'd respond if she says, "okay, so now what?" What do you want here?

I am taking a stab that he is a client of hers. I would keep all utterings of love out of a business transaction. I know when a couple of my clients say it, it makes me feel bad for them as there is no hope in hell of anything happening.

Every client that has told me they were in love me overstepped their bounds and I had to immediately end our business relationship together. I made the mistake of dating a client last year and the relationship quickly went to Hell (and never returned). He told me not to use male photographers, only female photographers...and was trying to turn me into someone I'll never be: monogamous. I got tired of him constantly accusing me of cheating and talking to my clients outside of business. Even my landlord thought he was nuts. I'll never mix business with pleasure again. When I hear stories like this, its a signal that a provider or hobbyist needs to tread with caution because when some people get rejected, things can get quite tense.

The deal going into P4P is that there are no strings attached. Most of the men are married, most of the women aren't interested in a relationship that overlaps with escorting.

you can become friends with a man that is 30 years or more older than you?

As long as he doesn't say it.  Saying it puts us both in an awkward position.  You're not supposed to do that to those you love.  Also, I would want to make sure its not affecting his personal life.  I'm not a home wrecker.  

I am nowhere near that mature. probably more like 13 than 30.

...and tip-toeing around them just causes problems (speaking for myself of course).

That's a good one.
In the brief time I've been a provider, I've encountered this more than I ever thought I would.
If I know that a client is falling in love with me, and the feeling is not mutual, I have to stop seeing them.  You can't come back from that, and it just gets messy.
But I have also fallen in love with a client. It IS possible for a client/provider relationship to cross the line from fantasy to reality.  You just have to go into it with your eyes WIDE open.