Absolutely, if you have a legitimate need to transmit on a TRS (which you may), your Motorola dealer will be able to set you up. Programming a TRS into a /\/\ Radio of any kind is not an easy task.
Actually, programming a TRS is rather easy once you've done them. Saber, MCS, MTS/MTX, they are all pretty much the same in programming. Honestly, I wish programming a scanner was as easy as programming a TRS! It's just called repetition, the more you do it, the easier it is.
Older TRS (i.e. non P25) the radio can be programmed to NOT affiliate on channel change. If the radio is just sitting there, even in scan mode, the TRS will never know that it exist (just like a scanner). Now, the minute you key up the radio, it's systems ID will be broadcast the the controller and if that ID is not authorized, it won't access the TRS. Many PS folks who don't have the ability to take home their portables (you have to leave it at the station even though it is assigned to you), they would simply get their system ID (easy to get, just call dispatch!), go to a Motorola dealer (not the one that programmed their system), show them their ID, give them their ID and have the radio programmed as a back up unit. No matter what anyone else says, it happens all around the US.
On a NEWER TRS - i.e. P25, it's not that easy. Especially on the XTS/XTL's, only 1 ID can be used as your radio serial number (not system ID, but "mother board ID") is transmitted. If your ID is being "bogarted" by another radio and it keys up, the system will see there are 2 of the same ID's but with different serial numbers. Most systems like that are set up to be flagged and a message sent to the system administrator. Most likely, a stun code will be sent out and brick your radio.
My conventional System Saber has GMRS (I'm a GMRS user) and just a couple PS UHF frequencies in it (because the Metro Atlanta area is almost totally P25), but the transmit is set to BLANK - all you get on the PS channels is a BLAAAANT noise when you key up on them meaning it can not transmit on it.
Yeah, the commercial equipment is more sensitive and has a richer audio to it, but they have limitations to them - smaller scan list (most will do a max of 16 channels), 1 frequency band (VHF-Lo, VHF-Hi, UHF), and most require expensive software and programming equipment.
Unless you have the $$$ to spend on the radio & equipment, stick to the scanner as it can save a lot of hassle if an officer want's to "investigate" you and your radio equipment.